Field of the Invention
This invention relates to a displaying device. More specifically, this invention relates to a displaying device which can receive a pinch out operation.
Description of the Related Art
An image forming apparatus, for example a MFP (Multi Function Peripheral), is usually equipped with an operation panel. The operation panel includes a display unit and a touch panel placed on the display unit. The display unit consists of a LCD (Liquid Crystal Display) or the like. The touch panel consists of a transparent touch pad. A user of the image forming apparatus touches the touch panel of the operation panel with fingers and can perform various operations of the image forming apparatus.
A portable telecommunication terminal device such as a smart phone, a tablet terminal device or the like becomes sophisticated. Then, cooperation between a portable telecommunication terminal device and an image forming apparatus is desired. More specifically, it is desired that (a) a user operates an image forming apparatus via a portable telecommunication terminal device, (b) documents stored in a portable telecommunication terminal device are printed by an image forming apparatus, and (c) documents in a portable telecommunication terminal device are moved to an image forming apparatus to store it in the image forming apparatus, and a plurality of users share the documents. Further, it is desired that (d) a user uses data such as an address book stored in a portable telecommunication terminal device, so that an image forming apparatus transmits images read by the image forming apparatus to an addressee designated from among addressees in the address book of the portable telecommunication terminal device, and (e) a user stores images read by an image forming apparatus in a portable telecommunication terminal device.
Some operation panels of image forming apparatuses and some portable telecommunication terminal devices can be operated by a multi touch operation. A multi touch operation is an operation in which an operation portion contacts at a plurality of points, and includes a pinch in operation and a pinch out operation, for example. According to such kind of portable telecommunication terminal devices, more direct and instinctive operations can be provided.
There are following techniques for a multi touch operation, for example. (a) An image being displayed on a touch panel is reduced, when two fingers are touching the touch panel and an operation which moves the two fingers closer to each other (a pinch in operation) is detected. (b) An image being displayed on a touch panel is enlarged, when two fingers are touching the touch panel and an operation which moves the two fingers away from each other (a pinch out operation) is detected. Document 1 below discloses the technique of enlarging an image around the center of the enlargement as the point moved from the midpoint of the two starting points of the pinch out operation in the direction determined based on displacement of the contact points of the pinch out operation, the distance of the movement is determined based on displacement of the contact points of the pinch out operation.
Documents 2 and 3 below disclose techniques of enlarging images being displayed on a display screen of a touch panel. An information processing apparatus of Document 2 below displays two button groups. The property which can be operated is assigned to one of the two button groups. The property for displaying status is assigned to another of the two button groups. The information processing apparatus makes the properties exchanged between the two button groups, when an arbitrary position in a displaying area corresponding to the button group to which the status display property is assigned is touched.
A touch input processing device disclosed in Document 3 below sets an enlarge operation area on a part of a display screen. In case that a touching point is in the enlarge operation area and the touching point is dragged, the touch input processing device switches a normal operation mode to an enlarge operation mode. The normal operation mode is a mode in which the real touching point is recognized as the touching position on the touch panel. The enlarge operation mode is a mode in which the coordinates of the touching point is converted, so that the real touching input in the enlarge operation area is recognized as a virtual touch input in all of the area of the touch panel.
Document 1: U.S. Pat. No. 7,844,915
Document 2: Japan Patent Publication No. 2006-72489
Document 3: Japan Patent Publication No. 2012-137837
According to the technique of Document 1, a user changes behavior of fingers which are performing a pinch out operation, so that the center of the enlargement (the target of the enlargement) can be moved from the midpoint of the pinch out operation to the desired location. However, the technique of Document 1 has a problem that the user can not perform a proper displaying with enlargement. The two fingers performing a pinch out operation do not move in straight line sometimes. The amounts of movement of two fingers differ from each other. For example, a user may perform a pinch out operation to make the midpoint of the pinch out operation as the center of the enlargement (perform an enlargement displaying in which the center of the enlargement is kept at the position of the midpoint of the pinch out operation). However, in reality, the center of the enlargement sometimes deflects from the desired point of the user. In case that the midpoint of the pinch out operation deflects from the location where the user desired as the center of the enlargement, a location not desired by the user may be the center of the enlargement. In consequence, the location the user desired as the center of the enlargement may move outside of the displaying area after the enlargement. In this situation, the user can not perform the operation continuously.
The problem in which users can not perform a proper display with enlargement arises in all kinds of displaying devices. The problem is especially significant for a portable telecommunication terminal device which works together with an image forming apparatus. In case that a portable telecommunication terminal device works together with an image forming apparatus, keys corresponding to software keys and hardware keys in the operation panel of the image forming apparatus are displayed on the touch panel of the portable telecommunication terminal device. Herewith, the user of the portable telecommunication terminal device operates the image forming apparatus via the portable telecommunication terminal device, having an operational feeling same as that of the operation via an operation panel of the image forming apparatus. However, the area of the touch panel of the portable telecommunication terminal device is far smaller than the same of the touch panel of the operation panel. Hence, keys being displayed on the touch panel of the portable telecommunication terminal device tend to be small. When a user operates the image forming apparatus via the portable telecommunication terminal device, the user sometimes enlarges the keys and the character inputting areas temporarily, to ensure the operability and the readability of the characters on the display of the portable telecommunication terminal device.